Casting molten metal



June 4, 1946. E. c. LYONS CASTING MOLTEEN METAL 2 Sheeis-Sheet 1' Filed Jan. 5, 1945 lNVENTO 516;; C M

Patented June 4, 1946 UNITED STATES PATENT OFFICE CASTING MOLTEN METAL Ellis C. Lyons, Chicago, 111.

Application January '5, 1945, Serial No. 571,502

7 claims. (01.22-73) This invention relates to the casting of easily or alloys, and has for its object the provision of an improved apparatus therefor.

Magnesium base metals or alloys, and othe easily oxidized metals, are customarily cast under a protective cover, such, for example, as an inert gaseous atmosphere, frequently produced by burning sulfur. Considerable skill and experience is required for the production of satisfactory castings, and even with due regard for the protection of the molten metal from oxidizing influences such as air, the amount of scrap p oduced is apt to be excessive. The present inVention aims to provide an improved apparatus for casting such metals, and particularly for castin slabs and ingots for rolling or equivalent mechanical working, in which cleaned and purified molten metal is cast, with a maximum of oxidizing influence, with the production of castings I of highly satisfactory and uniform quality and with a minimum of scrap.

The apparatus of the invention comprises a cating with the casting chamber. The casting 2 and thereafter the end of the casting then in the cooling chamber forms the corresponding end wall of the casting chamber during the next casting operation. In, the complete and preferred form of the apparatus, the casting in the cooling chamber is pushed by the immediately succeeding casting in the casting chamber, when the latter is itself pushed into the cooling chamber, on to supporting rollers or the like where the casting is sprayed with water for a complete chill. The

walls of the casting chamber and of the coolingchamber, and also-the reciprocable plungers, are artificially cooled in any appropriate manner.

The foregoing and other novel features of the invention which I believe to be patentably characteristic thereof are set forthin the appended claims. The principles of the invention will be best understood from the following description taken in conjunction with the accompanying drawings, in which,

Fig. 1 is a side elevation, partly in section and somewhat diagrammatic, of the casting end of evacuated molten metal is drawn into the casting drawings comprises a slab casting chamber or chamber through an intake duct communicating therewith and dependin into the body of clean and purified molten metal to be cast. When the casting chamber has been filled to the desired extent with molten metal, means are provided for terminating the evacuation of the chamber and for pushing the suitably solidified casting from the casting chamber into the cooling chamber. In the preferred form of the apparatus, a reciprocable plunger forms one end wall of the casting chamber, and means are provided for reciprocating this plunger throughout the length of the casting chamber. The contemplated synchronous operation of the apparatus is advantageously attained by an electrode adapted to extend into the casting chamber. 'When the electrode is grounded by molten metal in the casting chamber, suitably provided means operate (l) to retract the electrode from the casting chamber, (2) to terminate the evacuation of the casting chamber, and (3) to actuate the plunger reciprocating means to cause the plunger to push the suitably solidified casting from the casting chamber into the cooling chamber. A second reciprocable plunger forms the other end wall of the casting chamber for the first casting, and is then withdrawn through the cooling chamber,

mold 5 appropriately supported on a circular base 6. Molten metal is delivered to the castingchamher through a nozzle or port I secured in the partment I3 is in communication with a vacuum 4 pipe l8 connected to a suitable source of vacuum or reduced pressure l4 and having a solenoid controlled valve IS. The compartment I3 is hermetically closed at the top by a primary insulator l6 and cooperating gland nut l1 and a secondary insulator l8 and cooperating gland nut I9. An electric conductor or electrode 20 extends through the insulators ll, l6 and I8 and is adapted to be vertically reciprocated by the piston of a hydraulic cylinder 2|.

A reciprocable plunger 22 fits snugly in the casting chamber 5 and is adapted to be moved to and fro throughout the length of the chamber by the piston 01 a hydraulic cylinder 23. The plunger 22 forms one end of the casting chamber, and is provided with an interior compartment 24 for a circulating cooling medium, such as water.

Cooling medium is delivered to the compartment by an inlet pipe 25 and withdrawn through an outlet pipe 28.

The exterior or the casting Chamber is aircooled. T this end the casting chamber is surrounded by -a metal shield 21, appropriately spaced therefrom, and cooling air is delivered to the space between the casting chamber and the shield by air ducts 28. The space between the casting chamber and the metal shield may advantageously be provided with metal cooling fins 29 When the apparatus is to be operated, the not 2 is filled with clean and purified molten metal. The surface of the molten metal is preferably protected against oxidation by a suitable cover of fiux or inert gas. Additional clean and purlfied molten metal is siphoned into 'the pot 2, from time to time, so that casting may be continued indefinitely. The intake duct I depends into the body of molten metal to within a short distance from the bottom 01' the pot. For the first or initial casting, the plunger 22 is moved through the cooling chamber into position to form one end of the casting chamber. The plunger 22 forms the other end of the castin chamber. The electrode 20 extends a short distance into the casting chamber, and the valve II is open permitting evacuation of the chamber. Evacuation of the casting chamber draws molten metal through the intake duct 8 until the molten metal contacts the electrode 20. The electrode 20 may be adjusted to vary the length thereof that extends into the casting chamber, so that when theelectrode is contacted by the molten metal, the desired and predetermined amount of molten metal fills the casting chamber.

The electrode 20 is grounded by the contacting molten metal and the solenoid of the valve I5 is thereby energized from a source of electric energy 22 and the valve is closed, thus terminat- 1 8 evacuation of thecasting chamber. Simultaneously, the electromotive control means 24 for the hydraulic cylinder 2| is' energized and the piston thereof elevates the electrode 20 and retracts it from the casting chamber. At the same time, the electromotive control means 25 of the hydraulic cylinder 22 is energiud and the plunger 22 is advanced to put sufiicient pressure on the still molten or plastic metal in the casting chamber to completely fill the chamber. The artificial cooling of the walls of the casting chamber, including the plungers 22 and 22, promptly solidifies the metal in the chamber to a sufiicient extent to permit the plunger 22 to push the casting from the casting chamber into the cooling chamber. A; the first casting is pushed into the cooling chamber, the plunger 22 is withdrawn through the cooling chamber to an inoperative and out-of-the-way position, and thereafter the casting then in the cooling chamber forms the other end oi! the casting chamber.

The electromotive control means may advantageously be designed to .eflect, upon each energization, one complete cycle 01' movement (i. e. forward and back) of the plunger 22, whereupon the plunger is returned to its initial position, forming one wall or the casting chamber. The electrical circuits and operating means are simply and diagrammatically illustrated in Fig. l for explanatory purposes, and it is to be understood that various agencies and' instrumcntalities may be provided for efi'ecting the contemplated sequence oi operations characteristic of the invention. When the plunger 22 has returned to its initial position, a push button or similar type of electric switch 36, manipulated by the operation, (1) energizes the electromotive means 34 to cause the hydraulic cylinder 2| to lower the electrode 20 to its casting position extending a predetermined distance into the casting chamber, (2) energizes the solenoid oi. the vacuum valve IE to initiate evacuation of the casting chamber, and (if necessary) (3) sets the electromotive means 35 to efiect (upon the next contact of molten metal with the electrode 20) the next cycle 01' movement of the plunger 22. Thereupon the cycle or casting operations is repeated.

As the plunger 22 starts its iorward movement, it momentarily closes the port 1 ot the intak duct 8 and the vacuum portsl2. The vacuum valve It may advantageously be designed to permit the establishment of atmospheric pressure in the casting chamber behind the plunger 22, so that molten metal is not drawn into the chamberdur- Jing the cycle ot'movement oi the plunger. The

return movement of the plunger expels the air thus admitted to the casting chamber and at the same time establishes a reduced pressure in the chamber on the other side of the plunger. To maintain the advantage of the reduced pressure thus established in the casting chamber, during the return movement of the plunger 22, the switch 36 should be manipulated as the plunger moves past the ports 1 and I2, whereupon as the plunger clears and opens these ports the casting chamber is in communication with the source 01' vacuum I 4' and molten metal is drawn through the port I into the casting chamber.

When the second casting has suitablyset or solidified in the casting chamber, the plunger 22 pushes this casting into the cooling chamber and the casting then in the-"cooling chamber is pushed out of the cooling chamber onto rollers 21 or other suitable supports, where it .is completely chilled by a water spray from the perforated water pipe system 28.

' The operation of the apparatu is automatic and is entirely controlled by the grounding of the electrode 20 first by the molten metal in the casting chamber and then by the manually operated switch 26. Various control agenciesfother than those more or less diagrammatically indicated in Fig. 1, may be used for efiecting the contemplated synchronous and automatic operation of the various parts of the apparatus as hereinbeiore described. The single electrode 20 may. oi. course be replaced by a pair of electrodes adapted to be bridged by the molten metal in the casting chamber, as described in my copending application Ser. No. 571,501, filed January 5, 1945, thus avoiding the necessity of a grounded source oi.

- into the casting chamber for terminating evacuation thereof, means operative when said electric energy. Multiple inlet ducts may'be used in place 'of the single inlet duct 8 shown. The

purified and clean molten metal is withdrawn from the pot 9 with a minimum contact with any oxidizing influence, and little or no oxidation takes place in casting. The apparatus is particularly adapted for casting ingots, billets, slabs and the like, but may be constructed for the casting of any desired forms or shapes. While particularly adopted for the casting of magnesium base alloys, the invention may be applied with advantage to the casting of any easily oxidized metal.

I claim:

1. In an apparatus for casting molten metal, a casting machine having a casting chamber and a juxtaposed cooling chamber directly communicating with the casting chamber, an intake duct communicating with the casting chamber and adapted to depend into a body of'molten metal. means for evacuating the casting chamber, means operative when a predetermined amount of molten metal has been drawn into the castin chamber for terminating the evacuation thereof. and means operative when said predetermined amount of molten metal has been drawn into the casting chamber for pushing the suitably solidifled casting from the casting chamber into the cooling chamber.

2. In anapparatus for casting molten metal,

1 a casting machine having a casting chamber and a'juxtaposed cooling chamber directly communieating with the casting chamber, an intake duct communicating with the casting chamber and adapted to depend into a body of molten metal, an electrode adapted to extend into the casting chamber, means for retracting said electrode from the casting chamber when the electrode is contacted by molten metal in the casting cham ber, means for terminating the evacuation of the casting chamber when the electrode is contacted as aforesaid, and means operative when said electrode is contacted for pushing the suitably solidi- .fied casting from the casting chamber into the cooling chamber.

3. In an apparatus for casting molten metal, a casting machine having a casting chamber and a juxtaposed cooling chamber directly communieating with the casting chamber, an intake duct communicating with the casting chamber and adapted to depend into a, body oi molten metal, means for evacuating the casting chamber, an

electrode adapted to extend into the casting chamber, and means operative when the electrode is contacted by molten metal in the casting chamber for (l) retracting the electrode from the casting chamber, (2) terminating the evacuaplunger adapted to form the other end wall of tion of the casting chamber and (3) pushing the suitably solidified casting from the casting chamthe casting chamber, a second reciprocable plunger adaptedto i'ormthe other end'wall of the casting chamber, means for evacuating the casting chamber, means operative when a predetermined amount oi molten metal has been drawn the predetermined amount of molten metal has been drawn into the casting chamber for actuating said first-mentioned reciprocable plungerto push the suitably solidified casting from the casting chamber into the cooling chamber, and means for withdrawing said second reciprocable plunger through the cooling chamber whereby the end of the solidified casting in the cooling chamber forms one end wall of the'casting chamber dur-e ing the next casting operation.

5. In an apparatus for casting molten metal, a-

(2) actuating said reciprocable plunger to push the suitably solidified casting from the castin chamber into the cooling chamber.

6. In an apparatus for casting molten metal, a casting machine having a casting chamber and a juxtaposed cooling chamber directly communieating with the casting chamber, an intake duct communicating with the casting chamber and adapted to depend into a body of molten metal, means for evacuating the casting chamber, a reciprocable plunger forming one end wall of the casting chamber, means for reciprocating said plunger throughout the length of the casting chamber, an electrode adapted to extend into the casting chamber, and means operative when the electrode is contacted by molten metal in the casting chamber for (l) retracting the electrode fromthe casting chamber, (2) terminating the evacuation of the casting chamber and (3) actuating said plunger reciprocating means to cause the plunger to push the suitably solidified casting from the casting chamber into the cooling chamber.

7. In an apparatus for casting molten metal, a casting machine having a casting chamber and a juxtaposed cooling chamber directly communicating with the casting chamber, an intake duct communicating with the casting chamber and adapted to depend into a body of molten .metal.

a reciprocable plunger forming one end wall of the casting chamber, a second reciprocable th casting chamber, means for evacuating the casting chamber, an electrode adapted to extend into the casting chamber, means operative when the electrode is contacted by molten metal in the casting chamber for (1) terminating the evacuation 01' the casting chamber and 2) actuatin said first-mentioned reciprocable plunger to push the suitably solidified casting from the casting chamber into the cooling chamber, means for withdrawing said second reciprocable plunger through the cooling chamber whereby the end of the solidified casting in the cooling chamber a forms one end wall of the casting chamber during the next casting operation, and means for spraying a cooled casting with water when it is from the cooling chamber by said first-mentioned reciprocable plunger and the two immediately succeeding solidified castings.

ELLIS C. LYONS; 

